Pathophysiology of vaso-occlusive crisis in sickle cell disease is a complex process. A rapidly growing body of evidence implies the presence of a cytokine regulatory pathway related to RBC adherence to endothelial cell. Our preliminary work suggests the presence of abnormal levels of some cytokines in sickle cell patients. Prior to exploring the role of cytokines in the pathophysiology of VOC in sickle cell disease, we would like to have a more solid documentation.